1. Field of the Invention
This invention relates to electronic switching systems. More specifically, this invention relates to switching arrangements disposed to effectuate frequency conversion of the signal energy passing therethrough.
While the present invention is described herein with reference to a particular embodiment, it is understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional embodiments within the scope thereof.
2. Description of the Related Art
Satellite communication systems are increasingly used to facilitate signal transmission between geographically diffuse groups of users. In many such systems, a high-frequency switching network deployed on a satellite receives signal information from earth stations over a plurality of uplink frequency bands. Many conventional switching networks are designed to receive signal energy from uplink channels dispersed throughout spectral bands included within the microwave and millimeter wave frequency regions. Commonly used uplink bands include those spanning 5.9 to 6.4 GHz (C-band), 14 to 14.5 GHz (Ku-band), and 27 to 27.5 GHz (Ka-band). Similarly, signal energy is generally broadcast by the satellite over downlink bands extending from 3.7 to 4.2 GHz (C-band), 11.7 to 12.2 GHz (Ku-band), and 18 to 18.5 GHz (Ka-band).
Ideally, a satellite-based switching network would be able to convert the frequency of signal information received over any uplink channel to a desired downlink channel. In conventional switching arrangements each uplink channel generally includes a downconverter dedicated to translating the frequency of the received signal energy down to a single predefined intermediate frequency (I.F.). The I.F. signals are then routed by a switch matrix to an array of frequency upconverters. Specifically, each downlink channel utilizes one of the upconverters to translate the frequency of I.F. signal energy from the switch matrix up to RF (radio frequency) as a downlink signal.
Unfortunately, in order to safeguard against system failure a redundant component generally needs to be provided for each unique electronic element employed on the satellite. Since in conventional switching networks each frequency conversion element is unique (i.e. tuned to a single frequency), back-up upconverters and downconverters are generally respectively required for the receive and transmit channels. The large number of redundant devices in existing switching schemes increases system cost and complexity. Moreover, since weight minimization is typically a priority in the design of satellite communication systems this redundancy requirement may reduce the number of available channels.
Accordingly, a need in the art exists for a lightweight switching network suitable for use in a satellite communications system.